Changes of Sediment Distribution in a Channel Bifurcation – 3D Modeling

Abstract

This study is about sediment distribution problems in channel bifurcations. A mathematical model investigation was carried out using the 3D-modeling system, FLUENT.

For several geometries of channel bifurcations, 3D flow computations were performed using the k–ε model, in which sediment transport was simulated by particle trajectories. In the analysis of the particle distribution over the branches, much attention was paid to the dependence on discharge, distribution angle of diverting branch, and grain size.

In order to enable a systematic analysis, 12 runs were executed, combining two discharge distributions with two grain sizes (bed load and suspended load, respectively) in three channel geometries. Besides, a preliminary flow computation was performed in an additional geometry without a diverting branch for optimization of the grid size and adaptation lengths.

The purpose of this research is to get a better understanding of the physical processes of sediment distributions in channel bifurcations, deal with sediment management, and optimize river structures, for instance, inlet structures, or sluices.